Ohio Revised Code Title XXI. Courts Probate Juvenile § 2107.15

If a devise or bequest is made to a person who is one of only two witnesses to a will, the devise or bequest is void. The witness shall then be competent to testify to the execution of the will, as if the devise or bequest had not been made. If the witness would have been entitled to a share of the testator's estate in case the will was not established, the witness takes so much of that share that does not exceed the bequest or devise to the witness. The devisees and legatees shall contribute for that purpose as for an absent or afterborn child under section 2107.34 of the Revised Code.